title: On the use of Tedlar® bags for breath-gas sampling and analysis.
abstract: The storage capability of Tedlar® bags for gaseous compounds was assessed using on-line proton-transfer-reaction mass spectrometry (PTR-MS). Sample bags were filled with a mixture of volatile organic compounds (VOCs) at known quantities in the ppbv range. The test gas included alcohol, nitrile, aldehyde, ketone, terpene and aromatic compounds. PTR-MS enabled frequent bag-direct measurements of compound abundances over a 70 h storage period. Concentrations of all compounds decreased with bag storage time, with compound-specific decay rates. The most rapid decline in concentration levels was seen for water vapour in the bag, i.e. sample humidity. Such a decrease is particularly relevant for breath-gas samples, where water vapour content is high. Compound losses were attributed to a combination of adsorption to and diffusion through the bag walls. Storage property observations suggest that sample analyses made within 10 h of sampling offer adequate sample authenticity replication. Based on observations, an appropriate bag-cleaning procedure was established and assessed. Results indicated that acceptable bag cleanliness for breath-gas sampling is achievable.
authors.affiliation: Ionimed Analytik GmbH, Technikerstrasse 21a, A-6020 Innsbruck, Austria.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Beauchamp
authors.forename: Jens
authors.initials: J
authors.lastname: Herbig
authors.forename: Rene
authors.initials: R
authors.lastname: Gutmann
authors.forename: Armin
authors.initials: A
authors.lastname: Hansel